Vertical take off and landing (VTOL) aircraft with vectored thrust having continuously variable pitch attitude in hover

ABSTRACT

The presently disclosed embodiments relate to vertical takeoff and landing (VTOL) aircraft that have the capability of hovering in both a “nose forward” and a “nose up” orientation, and any orientation between those two. The disclosed aircraft can also transition into wing born (non-hovering) flight from any of the hovering orientations. In addition, certain of the disclosed embodiments can, if desired, use only vectored thrust control to maintain stable flight in both hover and forward flight. No control surfaces (e.g. ailerons, elevators, rudders, flaps) are required to maintain a stable vehicle attitude. However, the disclosure contemplates aircraft both with and without such control surfaces.

CROSS-REFERENCE TO RELATED PATENT APPLICATION(S)

This patent application is a continuation of and claims the benefit ofpriority to U.S. patent application Ser. No. 16/107,060, titled“Vertical Take Off and Landing (VTOL) Aircraft with Vectored ThrustHaving Continuously Variable Pitch Attitude in Hover” filed Aug. 21,2018, which claims the benefit of priority to U.S. ProvisionalApplication No. 62/548,546, titled “Vertical Take Off and Landing (VTOL)Aircraft with Vectored Thrust for Control and Continuously VariablePitch Attitude in Hover” filed on Aug. 22, 2017, the contents of whichare hereby incorporated by reference in their entirety for any purposewhatsoever.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The invention described herein was made in the performance of work undera NASA contract and by an employee of the United States Government andis subject to the provisions of Public Law 96-517 (35 U.S.C. § 202) andmay be manufactured and used by or for the Government for governmentalpurposes without the payment of any royalties thereon or therefore. Inaccordance with 35 U.S.C. § 202, the contractor elected not to retaintitle.

BACKGROUND

Vertical Take Off and Landing (VTOL) flight vehicles have been inexistence for many decades. However, maintaining stable flight duringall modes of flight including hover, transition, and forward flight hasalways been a challenge. The original flight controllers for VTOLaircraft had mechanical inertial gyroscope sensors to determine vehicleattitude. To date, VTOLs have fallen into two main categories;tailsitters, where the orientation of the aircraft changes 90 degreeswhen transitioning from hover to forward flight, or non-tailsitters,where the orientation is the same during hover and forward flight. Thepresent disclosure provides improvements over the state of the art.

BRIEF SUMMARY

The present disclosure is directed to embodiments of aircraft that cancontinuously adjust pitch, and if desired, roll and yaw. The disclosedembodiments allow for two or more orientations of a VTOL aircraft inhover mode and also allow outbound and inbound transitions fromwing-born forward flight into any hover orientation between nose-up andnose-forward. Multiple hovering orientations of a VTOL vehicle willallow pointing of an instrument, matching of vehicle orientation tolanding terrain or an oscillating landing surface, and also allowtransition to forward flight while maintaining constant altitude ortransition to forward flight with a vertical climb.

In some implementations, stable hovering and transition to stableforward flight and back to hover is maintained by vectoring of the threerotors with servo control and rotor speed control on all three rotors.In preferred implementations, commands for servo control and speedcontrol are provided from a suitable MEMS-sensor control board withstabilization firmware configured to operate the aircraft as set forthherein. It will be appreciated that other implementations can beprovided herein that can include more than three thrusters or rotors toachieve continuous hover attitude of the aircraft.

If desired, the aircraft can also include traditional control surfaces(ailerons, rudders, elevators, elevons, and the like) to enhance controlor replace some of the control from rotor thrust vectoring. For example,ailerons can be used for yaw control in a “nose-up” hovering orientationin lieu of thrust vectoring.

Thus, in some implementations, embodiments are provided of a method ofoperating an aircraft. The aircraft typically includes an elongatefuselage and a plurality of thrusters that are articulable with respectto the elongate fuselage. An illustrative method includes firstorienting the aircraft into a horizontal hover mode of operation whereinthe elongate fuselage is parallel to a stationary surface below theaircraft, or perpendicular to a gravitational vector. The method nextincludes transitioning the aircraft into a forward flight mode from thehorizontal hover mode by adjusting orientation of at least one of saidthrusters with respect to said elongate fuselage, wherein the elongatefuselage maintains its orientation with respect to the stationarysurface in the forward flight mode. The method further includestransitioning the aircraft into a vertical hover mode of operation fromthe forward flight mode by adjusting orientation of at least one of saidthrusters with respect to said elongate fuselage wherein the elongatefuselage is perpendicular to the stationary surface below the aircraft.

In some implementations, the method can further include transitioningthe aircraft into the forward flight mode from the vertical hover modeof operation, wherein the elongate fuselage is horizontal to thestationary surface, (perpendicular to the gravity vector). If desired,the method can include continuously varying at least one of the pitch,yaw and roll of the aircraft to match movement of a landing surfaceunderneath the aircraft that is experiencing motion. For example, thelanding surface can be a deck of a moving ship, or a platform mounted ona moving vehicle.

In some implementations, methods can be provided of operating a VTOLaircraft that includes maintaining the elongate fuselage in anorientation parallel to ground of varying grade, or evenness, during theforward flight mode by continuously adjusting the pitch of the fuselage.If desired, the method can include transitioning a VTOL aircraft into ahover mode and aligning the elongate fuselage with a slanted landingsurface, and landing the aircraft. If desired, the method can furtherinclude transitioning into a hover mode and aligning the elongatefuselage vertically, and landing the aircraft on a slanted landingsurface. If desired, the method can further include transitioning into avertical flight mode wherein the aircraft advances vertically upwardlyin the vertical flight mode, and further wherein the elongate fuselageis vertically oriented in the vertical flight mode, parallel to thegravity vector. If desired, it is also contemplated to transition intothe forward flight mode from the vertical flight mode. In variousimplementations, the method can further include adjusting the pitch,yaw, or roll of the aircraft during the forward flight mode by using atleast one control surface. Alternatively, the method also contemplatesadjusting the pitch, yaw, and roll of the aircraft during the forwardflight mode by using only the plurality of thrusters.

The disclosure further provides an aircraft having an elongate fuselageand a plurality of thrusters that are articulable with respect to theelongate fuselage. The aircraft is configured and adapted to becontrollably oriented into a horizontal hover mode of operation whereinthe elongate fuselage is parallel to a stationary surface below theaircraft. The aircraft is further configured and adapted to becontrollably transitioned into a forward flight mode from the horizontalhover mode by adjusting orientation of at least one of said thrusterswith respect to said elongate fuselage, wherein the elongate fuselagemaintains its orientation with respect to the stationary surface in theforward flight mode. The aircraft is further configured and adapted tobe controllably transitioned into a vertical hover mode of operationfrom the forward flight mode by adjusting orientation of at least one ofsaid thrusters with respect to said elongate fuselage wherein theelongate fuselage is perpendicular to the stationary surface below theaircraft.

In some implementations, the aircraft can include at least threearticulable thrusters. Each of the articulable thrusters can beconfigured to articulate about at least one axis to alter theorientation of thrust produced by each respective thruster.

In some implementations, at least one of the thrusters can be configuredto articulate about two axes. For example, the at least one thrusterconfigured to articulate about two axes can be configured to articulateabout a first axis that is parallel to the direction of thrust. In someimplementations, the aircraft can include at least two articulablethrusters, wherein each of the articulable thrusters is configured toarticulate about at two axes to alter the orientation of thrust producedby each respective thruster.

Various implementations of the aircraft also include a control systemfor controlling the orientation of said plurality of thrusters with saidfuselage, wherein said control system includes at least one controllerfor receiving orientation data indicative of the physical orientation ofsaid aircraft. The control system is configured to receive and processdata indicating the shape of terrain disposed below the aircraft. Insome implementations, the control system is configured to receive andprocess visual data indicating the shape of terrain disposed below theaircraft. The control system is also configured to process data receivedfrom at least one motion sensor to determine orientation of the aircraftand to determine any adjustments that need to be made in the orientationor speed of any of the thrusters to change the orientation of theaircraft. For example, the control system can be configured toautomatically match the pitch, yaw, and roll of the aircraft to alanding surface disposed below the aircraft that may be moving (such asa naval vessel, surface vehicle or another aircraft), and land theaircraft on the landing surface.

These and other features, advantages, and objects of the presentinvention will be further understood and appreciated by those skilled inthe art by reference to the following specification, claims, andappended drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a side plan view of an illustrative aircraft in accordancewith the present disclosure in a forward flight configuration.

FIG. 1B is a top plan view of the aircraft of FIG. 1 .

FIG. 2A is a side plan view of the aircraft of FIG. 1 in a hover modewith the fuselage of the aircraft in a horizontal orientation.

FIG. 2B is a top plan view of the aircraft of FIG. 1 in a hover modewith the fuselage of the aircraft in a horizontal orientation, whereinthe propellers are displaced rotationally 90 degrees with respect toFIG. 2A for purposes of illustration.

FIGS. 3A-3D illustrate a flight sequence of the aircraft of FIG. 1starting in a hover mode wherein the fuselage is parallel to the groundtransitioning to a forward flight mode wherein the thrusters are rotated90 degrees with respect to the hover mode.

FIGS. 4A-4D illustrate a flight sequence of the aircraft of FIG. 1starting in a forward flight mode and transitioning to a hover mode.

FIGS. 5A to 5D illustrate a flight sequence of the aircraft of FIG. 1starting in a forward flight mode and transitioning to a tail sittinghover mode.

FIGS. 6A to 6C illustrate a flight sequence wherein the aircraft of FIG.1 transitions from a forward flight mode near the ground to a verticalflight mode while hugging terrain.

FIGS. 7A and 7B are side plan views of an alternate embodiment of anaircraft in accordance with the disclosure that utilizes jet or ductedfan thrusters in place of propeller based thrusters.

FIGS. 8A and 8B are top plan and side plan views, respectively, of analternate embodiment of an aircraft in accordance with the disclosurethat utilizes two thrusters that can articulate about two orthogonalaxes in a hover mode.

FIGS. 9A and 9B are top plan and side plan views, respectively, of theembodiment of FIGS. 8A and 8B in a forward flight mode configuration.

DETAILED DESCRIPTION

For purposes of description herein, the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the invention as oriented in FIG. 3 . However,it is to be understood that the invention may assume various alternativeorientations and step sequences, except where expressly specified to thecontrary. It is also to be understood that the specific devices andprocesses illustrated in the attached drawings, and described in thefollowing specification, are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificdimensions and other physical characteristics relating to theembodiments disclosed herein are not to be considered as limiting,unless the claims expressly state otherwise.

The presently disclosed embodiments relate to vertical takeoff andlanding (VTOL) aircraft that have the capability of hovering in both a“nose forward” and a “nose up” orientation, and any orientation betweenthose two, as well as methods and equipment for operating such vehicles.The disclosed aircraft can also transition into wing born (non-hovering)flight from any of the hovering orientations. This capability to hoverin multiple orientations can be advantageous for tasks such as pointingof instruments that are in the fuselage or wing of the aircraft withoutthe need for a gimballed instrument platform. The disclosed aircraft canalso orient itself with the slope of the terrain for landings onnon-horizontal surfaces. A continuously variable hover orientation alsoallows the flight vehicle to match its pitch oscillation movement tothat of a rolling deck on a ship, thus preventing a rotor tip strike onthe deck or a tip over condition on the landing gear. In addition, thedisclosed aircraft can, if desired, use only vectored thrust control tomaintain stable flight in both hover and forward flight. No controlsurfaces (e.g. ailerons, elevators, rudders, elevons, flaps, etc.) arerequired to maintain a stable vehicle attitude. However, the disclosurecontemplates aircraft both with and without such control surfaces.

The advantage of the disclosed embodiments over previous types of VTOLvehicles is that the orientation of the vehicle airframe can be changedin hovering mode to perform various tasks including pointing ofinstruments without the need for an instrument gimbal and matching ofvehicle pitch and roll attitude to surfaces that may not be horizontal(e.g. mountain side) or may be changing orientation rapidly with time(e.g. a ship in rough seas or moving land vehicle). In addition theability of the vehicle to hover in two or more orientations allows it totransition to forward flight in a number of ways that has not previouslybeen a capability of VTOL aircraft. For example, some of the disclosedembodiments can transition from hovering into forward flight from a noseup hovering orientation by accelerating vertically and then changingorientation by 90 degrees for forward flight. This capability can be agreat advantage if the vehicle is coming out of a steep-walled valley oran urban environment where horizontal distance is limited for transitionto forward flight. Alternately, if the vertical distance fortransitioning to hover or forward flight is constrained (such as in atunnel or indoor environment), embodiments made in accordance with thepresent disclosure can maintain a constant altitude during thetransition.

Embodiments made in accordance with the present disclosure can be usedin a wide variety of applications including military applications,commercial agriculture, infrastructure assessment, atmospheric science,and radio controlled hobby aircraft, for example.

With the advent of high speed microprocessors combined withmicro-electrical-mechanical systems to determine vehicle attitude andaccelerations, Applicant has come to appreciate that controlling a VTOLflight vehicle has become easier and less costly. This has the potentialto open up a new region of VTOL aircraft design space that was notpreviously explored, except for a few high-cost military vehicles. Inaddition, Applicant has come to appreciate that new electric motor andelectric motor speed control (ESC) technologies for very precise motorspeed control permit very precise thrust adjustment to maintain vehicleattitude control in hover and forward flight.

For purposes of illustration, and not limitation, as illustrated inFIGS. 1A and 1B, the disclosure further provides an aircraft, orvehicle, 100 having an elongate fuselage 102 and a plurality ofthrusters disposed in nacelles 110, 116 that are articulable withrespect to the elongate fuselage 102, wherein the nacelles 110, 116 areoriented in a manner to facilitate a conventional forward flight mode.Specifically, the nacelles 110, 116 can be controllably rotated aboutpivots 110 a, 116 a over a range of angular motion (e.g., about 75degrees to about 120 degrees, more preferably about 80 degrees to about100 degrees). The nacelles 110, 116 can be controllably actuated torotate using suitable actuators (e.g., electric stepper motors, electricservo motors, hydraulic actuators, and the like). In the embodiment ofFIG. 1A, two conventional propellers 112 are provided on the nacelles110 mounted on the wing 104, whereas a pusher propeller 114 is mountedon the nacelle 116 near the tail 108 and the horizontal stabilizer 106.

FIG. 1B illustrates a top plan view of the aircraft 100 in forwardflight mode, further illustrating a controller 150, discussed in furtherdetail below, that is operably coupled to the control surfaces, (flaps,ailerons, elevators, elevons, rudder, etc.) as well as to the actuators(not shown) that articulate the nacelles, and the thrusters themselvesfor driving the propellers 112, 114. The control pathways areschematically represented in dashed lines as is the controller 150.

FIGS. 2A and 2B show side plan and top plan views, respectively, of theaircraft, or vehicle, of FIG. 1A, in a horizontal hover mode. Asillustrated in FIG. 2A, the nacelles 110 have been rotated about pivots110 a by about ninety degrees, wherein rotating propellers 112 pull theaircraft upwardly. Likewise, nacelle 116 has been rotated downwardlyabout 90 degrees in the hover mode to push up the tail section of theaircraft. The controller preferably continuously adjusts the orientationof the nacelles 110, 116 in order to maintain the fuselage 102 in adesired orientation. It will be appreciated by those of skill in the artthat the elongate fuselage can have any desired shape, and may berelatively long, relatively short, wide, narrow, tall, etc. It will beappreciated that the fuselage is being referred to as being “elongate”in this disclosure in order to help describe orientation of thefuselage's “length” with respect to a coordinate system or a surface(e.g., the ground or a wall). It will be further appreciated that, whilesingle propellers are illustrated on each nacelle 110, 116,counter-rotating propellers may alternatively be used on some or all ofthe nacelles. It will be still further appreciated that any desirednumber of nacelles may be used on the aircraft to help achieve anydesired design objective.

It will be appreciated that aircraft in accordance with the disclosurecan be operated in a variety of manners due to their versatility.

For example, FIGS. 3A-3D illustrate a flight sequence of the aircraft ofFIG. 1 starting in a hover mode wherein the fuselage is parallel to theground transitioning to a forward flight mode wherein the thrusters arerotated 90 degrees with respect to the hover mode. “G” in the figuresenclosed within an arrow indicate the direction of the gravitationalvector. As illustrated, the aircraft 100 can start from a position nearthe ground in FIG. 3A (or even from a landed position in which caselanding gear can be present, but is not specifically illustrated). Theaircraft can then simply climb in altitude and rapidly transition toforward flight as illustrate in FIG. 3D without significantly adjustingthe pitch of the fuselage 102. Alternatively, the fuselage 102 can bepitched gently into a nose upward position as the nacelles 110, 116 arerotated as illustrated in FIG. 3B. As the nacelles 110, 116 continue toarticulate toward a forward flight mode, the fuselage 102 begins tolevel as illustrated in FIG. 3C, and finally levels fully when thenacelles 110, 116 have completed their articulation. It should be notedthat, to some extent, the aircraft can be caused to move forward andupwardly simultaneously, or may be maintained largely in position duringtransition from hover mode to forward flight mode by controlling theamount and direction of thrust provided by the propellers 112, 116.

As an alternative illustration, FIGS. 4A-4D depicts a flight sequence ofthe aircraft of FIG. 1 starting in a forward flight mode andtransitioning to a hover mode. As indicated, the aircraft begins inforward flight mode as presented in FIG. 4A wherein the axes of rotationof the propellers are parallel to a longitudinal central axis of thefuselage 102. Then, as illustrated in FIG. 4B, the nacelles beginarticulating toward their hover mode positions, and the fuselage can bepermitted to tilt slightly, as desired. The nacelles continue to rotatetoward hover mode as illustrated in FIG. 4C, and finally, as illustratedn FIG. 4D, the aircraft has attained hover mode. While in hover mode,the aircraft can remain stationary, move forward, backward, to the sideand/or downward simultaneously. Moreover, the pitch, yaw and/or roll ofthe aircraft can be selectively altered by the controller to attain anydesired orientation.

FIGS. 5A to 5D illustrate a flight sequence of the aircraft of FIG. 1starting in a forward flight mode and transitioning to a tail sittinghover mode. Specifically, as illustrated in FIG. 5A, the aircraft ispresented once again in a forward flight mode. As illustrated in FIGS.5B and 5C, the nacelles 110, 116 once again begin to articulate aboutpivots 110 a, 116 a, causing the fuselage to move out of a horizontalorientation toward a vertical orientation as illustrated in FIG. 5D.Landing gear (not shown) can be provided to permit the aircraft to landon its tail. From such a landed position, or from a vertically orientedhovering position, the aircraft can then, if desired, climb rapidly withminimal aerodynamic resistance, and then maintain a hover mode, ortransition into a forward flight mode.

FIGS. 6A to 6C illustrate a flight sequence wherein the aircraft of FIG.1 transitions from a forward flight mode near the ground to a verticalflight mode while hugging terrain. Specifically, FIG. 6A presents theaircraft traveling forward along relatively even terrain thattransitions to a vertical surface. FIG. 6B shows the nacelles 110, 116beginning to articulate, thereby changing the pitch of the fuselageuntil it attains a vertical orientation as illustrated in FIG. 6C, whichpermits the aircraft to climb rapidly along the vertical surface. Suchversatility can be of particular use when it is desired to minimize thedetectability of the aircraft. This stealth can be enhanced by paintingthe vehicle in color(s) matching the terrain, and/or by making theaircraft from materials that provide a minimal radar signature.

FIGS. 7A and 7B are side plan views of an alternate embodiment 200 of anaircraft in accordance with the disclosure that utilizes jet or ductedfan thrusters in place of propeller based thrusters. The nacelles 210,216 articulate about pivots 210 a, 216 a to transition from a forwardflight mode into a horizontal hover mode, and/or into a vertical hoveror flight mode, as desired. It is also contemplated to provide thenacelles 210, 216 with a further capability to pivot the nacelles aboutan axis that is parallel to a longitudinal axis of the fuselage inplanes of rotation 210 b, 216 b. Stated another way, the enginesthemselves can be rotatably mounted within nacelles 210, 216 and bearticulable by the controller, such as by one or more geared steppermotors that engage an arcuate rack mounted on the engine (not shown).This permits the thrusters to be vectored from side to side when in thehorizontal hover mode illustrated in FIG. 7B to help the aircrafttranslate sideways, or to permit it to rotate in place horizontallyabout a vertical axis that is orthogonal to a longitudinal axis of thefuselage.

In further accordance with the disclosure, FIGS. 8A and 8B are top planand side plan views, respectively, of an alternate embodiment of anaircraft 300 in accordance with the disclosure that utilizes twothrusters, mounted in nacelles 310, 316, that can articulate about twoorthogonal axes while in a hover mode. FIGS. 9A and 9B are top plan andside plan views, respectively, of the embodiment of FIGS. 8A and 8B in aforward flight mode configuration. The portions of aircraft 300 aresimilar to those of FIG. 1 . For example, fuselage 302 includes a wing304, a horizontal stabilizer 306, and tail 308 with a rudder, if desired(not shown).

A first nacelle 310 is located on the nose of the aircraft, and a secondnacelle 316 is located on a tail of the aircraft. The tail nacelle 316is articulable about a pivot 316 a as the previous embodiments. Also, asecondary pivot plane 316 b (oriented into and out of the page of FIG.8A) is provided as with the embodiment of FIGS. 7A and 7B, such that thenacelle 316 can be controllably pivoted about the axis ofcounter-rotating propellers 314 at the location of plane 316 b.Similarly, the nacelle 310 mounted in the nose of the aircraft isarticulable about pivot 310 a, and about the axes of rotation of thecounter-rotating propeller pairs 312, 314 at the location of plane 310b. Counter-rotating propellers 312, 314 are preferably used that areconfigured to impart a minimal net torque to the fuselage 302 ofaircraft 300. The axes of propellers 312, 314 can be along the sameaxis, or their axes can be offset and be parallel to each other when thenacelles are oriented in the forward flight mode as illustrated in FIGS.9A and 9B. Thus, in the implementation of FIGS. 8A-(b, both of thethrusters can be configured to articulate about two axes—the axes ofpivots 310 a, 316 a, and the axes of the propellers 312, 314 in order tocontrol the roll of the aircraft. The controller (e.g., 150) can beconfigured to control all movements of the nacelles and the motors, aswell as the control surfaces, if so equipped.

As to the second axis of rotation of each nacelle to control roll, theaxis of rotation may be coaxial with the axis of rotation of thepropellers on each nacelle, or the axes of rotation of the nacelle tocontrol roll may be displaced (e.g., vertically) from the axis ofrotation of the propeller. The center of gravity of the aircraft shouldbe below or above the line of action of the second axis of rotation toensure that roll torque is achieved.

As mentioned above with reference to FIG. 1 , various implementations ofthe aircraft also include a controller 150 for controlling theorientation of the thrusters with respect to the fuselage. Preferably,the controller 150 is also configured to receive orientation dataindicative of the physical orientation of the aircraft (e.g., 100, 200,300), such as from motion sensors (not shown) disposed in the fuselageand/or the nacelles. The controller 150 is also preferably configured toreceive and process data indicating the shape of terrain disposed belowthe aircraft. In some implementations, the control system 150 isconfigured to receive and process visual data indicating the shape ofterrain disposed below the aircraft. The visual data can be in thevisible spectrum as well as other spectrums (e.g., infrared and otherspectrums). The controller 150 is also preferably configured todetermine any adjustments that need to be made in the orientation orspeed of any of the thrusters (whether propeller, jet or fan driven) tochange the orientation of the aircraft. For example, the controller canbe configured to automatically match the pitch, yaw, and roll of theaircraft to a landing surface disposed below the aircraft that may bemoving (such as a naval vessel, surface vehicle or another aircraft),and land the aircraft on the landing surface. As will be appreciated,controller 150 can control the speed and orientation of each thrusterindependently of one another. A power supply, such as a battery (notshown) is also provided for powering the vehicle.

Various embodiments of a controller 150 can be used. In preferredimplementations, commands for servo control and speed control areprovided from a suitable MEMS-sensor control board with stabilizationsoftware that is specifically configured to operate the aircraft as setforth herein. In one example, an experimental scale aircraft having thestructural configuration set forth in FIG. 1A was constructed utilizinga Hobbyking KK2.1.5 Multi-rotor LCD Flight Control Board With 6050MPUAnd Atmel 644PA. A servo controlling the motion of each nacelle 110,110, 116 was connected to the board as well as to each of three electricthruster motors located in the nacelles. A reconfigurable code run onthe control board was used that was modified to mix the hover flightcontrol settings with the forward flight control settings in apredetermined ratio in order to achieve a desired fuselage hover angle.In this particular example, settings for a “second” hover orientationwere used as the forward flight mode settings. It will be appreciated,however that any suitable controller can be used, with suitablyconfigured, or custom coded control software to help produce aircraft inaccordance with the present disclosure.

As discussed above, the disclosed embodiments of aircraft are configuredto be extremely versatile. Aircraft in accordance with the presentdisclosure can be configured to take off from and/or land on movingsurfaces, such as those of naval vessels, surface vehicles, and, ifdesired, onto other aircraft.

Though aspects and features may in some cases be described in individualfigures, it will be appreciated that features from one figure can becombined with features of another figure even though the combination isnot explicitly shown or explicitly described as a combination. It isintended that the specification and drawings be considered as examplesonly, with a true scope of the invention being indicated by thefollowing claims.

What is claimed is:
 1. A non-transitory computer-readable mediumcomprising computer-executable instructions that when executed by aprocessor, cause the processor to at least: generate a horizontal hovermode control signal configured to orient an aircraft having an elongatefuselage and a plurality of thrusters that are articulable with respectto the elongate fuselage into a horizontal hover mode of operation,wherein the horizontal hover mode control signal is configured to causethe elongate fuselage to be parallel to a stationary surface below theaircraft; generate a forward flight mode control signal configured totransition the aircraft into a forward flight mode from the horizontalhover mode, the forward flight control signal configured to at leastadjust orientation of at least one of said thrusters with respect tosaid elongate fuselage, wherein the elongate fuselage maintains itsorientation with respect to the stationary surface in the forward flightmode; and generate a vertical hover mode control signal configured totransition the aircraft into a vertical hover mode of operation from theforward flight mode, the vertical hover mode control signal configuredto at least adjust orientation of at least one of said thrusters withrespect to said elongate fuselage wherein the elongate fuselage isperpendicular to the stationary surface below the aircraft.
 2. Thenon-transitory computer-readable medium of claim 1, the medium furthercomprising instructions that when executed by the processor, cause tothe processor to at least: generate a second forward flight mode signalconfigured to transition the aircraft into a forward flight mode fromthe vertical hover mode of operation, wherein the elongate fuselage ishorizontal to the stationary surface.
 3. The non-transitorycomputer-readable medium of claim 1, the medium further comprisinginstructions that when executed by the processor, cause to the processorto at least: receive movement data comprising electronic informationrelating to movement of a landing surface; and in response to at leastthe received movement data, transmit a signal configured to continuouslyvary at least one of the pitch, yaw and roll of the aircraft to matchmovement of a landing surface underneath the aircraft that isexperiencing motion.
 4. The non-transitory computer-readable medium ofclaim 3, wherein the movement data comprising data relating to themovement of a vessel over water.
 5. The non-transitory computer-readablemedium of claim 1, the medium further comprising instructions that whenexecuted by the processor, cause to the processor to at least: generatea maintain control signal configured to be transmitted while theaircraft is in forward flight mode, the control signal configured tomaintain the elongate fuselage in an orientation parallel to a groundsurface of varying evenness by continuously adjusting the pitch of thefuselage.
 6. The non-transitory computer-readable medium of claim 1, themedium further comprising instructions that when executed by theprocessor, cause to the processor to at least: generate a landingcontrol signal configured to transition the aircraft into a hover mode,align the elongate fuselage with a slanted landing surface, and land theaircraft on the slanted landing surface.
 7. The non-transitorycomputer-readable medium of claim 1, the medium further comprisinginstructions that when executed by the processor, cause to the processorto at least: generate a landing control signal configured to transitionthe aircraft into a hover mode, align the elongate fuselage vertically,and land the aircraft on a slanted landing surface.
 8. Thenon-transitory computer-readable medium of claim 1, the medium furthercomprising instructions that when executed by the processor, cause tothe processor to at least: adjust the pitch, yaw, or roll of theaircraft during the forward flight mode by using at least one controlsurface.
 9. The non-transitory computer-readable medium of claim 1, themedium further comprising instructions that when executed by theprocessor, cause to the processor to at least: adjust the pitch, yaw,and roll of the aircraft during the forward flight mode by using onlythe plurality of thrusters.